U.S. Pat. No. 5,515,606, Albeck et al., assigned to the assignee of the present application, and the disclosure of which is hereby incorporated by reference, describes a method to wire electrical terminals of electrical devices, aggregates or assembled units or systems, which is particularly adapted to achieve high efficiency, reliable operation, and avoidance of erroneous wiring, or errors. The method can be used in general, but is especially suitable for wiring luminaires, especially fluorescent light fixtures, which have within the luminaire separate accessory apparatus, such as ballasts. The patent describes a method which permits complete automation of the wiring of such luminaires or, in general, electrical apparatus, aggregates, assemblies and systems. It permits elimination of preassembled, or precut lines, as well as wiring harnesses, since it permits direct association of the required wires with the device, or terminals the wires are to serve.
The method is carried out, by means of a position controlled mechanical wire placement element, hereinafter and for brevity, a wiring finger, in such a way that, first, the electrical device or system has terminal blocks or the like preassembled therein. The location of the fixture, as well as of the terminals, is fixed and determined in accordance with a positioning raster. By relative movement between the preassembled device, or system, and the wiring finger, a first connection terminal is brought in the operating region of the finger and is positioned with respect thereto in proper wire-laying orientation. The wiring finger then introduces one end of an electrical wire supplied, for example, from an external wiring supply, such as a supply spool, into a contacting zone of the first terminal. It is fixed in position at the same time when an electrical contact is effected. Further relative movement between the preassembled electrical device or system and the finger, along a predetermined path, results in positioning of the line, sequentially, to further terminals all within the operating range of the wiring finger, and properly oriented positioning of the finger relative to the next terminal. During this relative movement, the line is supplied to the finger with a suitable length corresponding to the line positioning path. The continuously supplied line is introduced, at any terminal, into a contacting zone. An electrical contact is made, and the position of the wire is fixed at the terminal. The wire may be cut or not; if not, a through-wired contact is made.
The line, which is so positioned, is cut at the final end in the region of the last terminal. The cut end of the line, as well as the terminal, are so constructed that the cut end is safely received in the terminal and protected against accidental contact. The line positioning element, that is for short, the finger, is so constructed that it has a positioning finger element projecting from a housing. A conductor duct is located within the finger element. A controlled feed for the wire is provided. The finger is controlled, for example, by an industrial robot, or automatic positioning system in accordance with a preprogrammed wiring path, which places the finger adjacent the respective terminal to be contacted. The contacting zone of the terminal is formed as a Slit Blade Insulation Piercing Connector—hereinafter for short SBIPC—and the line which is to make contact at the terminal is pressed into the slit of the slit blade connector.
To place the wire into the SBIPC, a pressure element is provided movably secured on the finger and movable transverse to the axial orientation of the terminal end of a wire guide duct in the finger. The pressure element can be moved between two positions, one being a quiescent or rest position, remote from the terminal end of the wire duct, and the other a working position in which it projects over a line extending from the wire duct at one side, or at least is in approximate alignment with the upper side of the exit opening of the wire duct.
A separately controllable knife blade is located between the pressure element and the finger element as such, which cooperate with the opening surface of the wire exit opening of the wire duct, to permit cutting off the wire at the last terminal end when the positioning path of the wire has been run through.
The terminals are so constructed that they retain all the terminals within a contacting zone, and are surrounded within a housing of insulating material. The housing is formed with at least one introduction slot, open at an end, to receive the line, and further includes the SBIPC, which has its insulation piercing slit oriented to the introduction slot. The upper end of the slit is open. The SBIPC is retained in the insulating housing part in a manner to ensure that accidental contact therewith is not possible.
The housing, at least in one side thereof, and adjacent the introduction slot has an extension in form of a groove-like recess or depression, the width of which is larger than the width of the introduction slot, and the dimensions of which are so determined that a free end of a line which made contact to the SBIPC can be received in this slot, or groove-like extension. The slot or groove-like extension, as well as the housing, is generally matched to the dimensions of the wire-positioning finger and of the pressure element thereof, so that this extension can carry out a dual function:
(1) It receives a cut end of the wire at the last terminal of the wire positioning path in such a manner that it is safely retained against accidental contact. This means that the blank end of the wire cannot be reached from the outside in accordance with standard testing procedures, or at standard testing probe.
(2) The extension functions as a guide groove for the positioning finger of the positioning tool as the finger is moved over the terminal connection, and upon pressing the wire into the SBIPC by the pressure element.
The second function of the groove-like extension or depression at the terminal requires a predetermined minimum width of the depression which is substantially larger than the diameter of the wire, including its insulation. This is due to the size of the positioning finger which engages into the extension. The walls adjacent this extension duct or groove are thicker than the outer diameter of the wire insulation of the wire which is placed by the finger and located in the guide groove. This thickness dimension must also be extended to permit for slight shifting of the wire in the guide groove.
If multi-pole terminals are used, a terminal block will have a substantial width, due to the width of the slit or groove-like extension or depression of the housing at any one terminal, which is of substantially greater width than that of the wire, including insulation, itself. Some minimum dimension could not be decreased below that which is given by the width of the positioning finger and the required wall thicknesses, which are established in view of the air and surface creep path necessary for effective insulation between poles or terminals.
There are many applications where it is necessary, for example, due to space reasons, to closely move together terminals of a terminal block, or, otherwise, to make the individual terminals narrower than it was possible while retaining the groove-like depressions or extensions of the housing to permit the positioning finger to engage therein. In actual practice, it is desirable that such a device or assembly might have connection terminals of the well-known type which have grooves or extensions capable of receiving the width or thickness of the positioning finger, but which also have narrower connection points. If such narrower connection points, for space reasons, are also required, it was not possible to completely automatically wire a luminaire, or other device independently and without change in tools or wiring apparatus, in other words, to completely automate wiring of such devices or apparatus, entirely independently of the special construction of the terminals.